Transmission and control mechanism



Aug. 15, 1933. F. A. PARSONS TRANSMISSION AND CONTROL MECHANISM Filed Dec. 3, 1931 5 Sheets-Sheet l Aug. 15, 1933. PARSONS 1,922,633

TRANSMISSION AND CONTROL MECHANISM Filed Dec. 3, 1931 5 Sheets-Sheet 2 Aug. 15, 1933. F. A. PARSONS TRANSMISSION AND CONTROL MECHANISM Filed Dec. 5, 1951 5 Sheets-Sheet 5 m Em g- 1933- F. A. PARSONS 1,922,633

TRANSMISSION AND CONTROL MECHANISM Filed Dec. 3, 1931 5 Sheets-Sheet 4 11 F'Lg. 9

TRANSMISSION AND CONTROL MECHANISM Filed Dec. 3, 1931 5 Sheets-Sheet 5 n INVENTOR F1912 Ma WW Patented Aug. 15, 1933 UNITED STATES TRANSMIS SIGN AND CONTRO REESE-LAN 31H Fred A. Far-sons, Milwcuee, Wis.,

, Kearney Wis.

Application December 3, 1931..

5 Claims.

This invention relates to milling machines and more particularly to drive and control mechanism for cutting helical grooves or threads with such machines.

When used for such purposes the work is traversed axially and rotated in exact timing with the axial movement to generate the desired lead or angle of groove. The timing is accomplished by suitable gearing connecting the table screw and the work. For relatively large helix angles it is satisfactory or preferable to apply the driving power to the table screw which in turn drives the work through the gearing, but for small helix angles it is preferable to apply driving power to drive the table screw through the connecting gearing. In either event it is desirable to provide an automatic trip to simultaneously stop both the traverse and rota tional movements when the cutting operation is completed. The transmission and trip devices previously incorporated in milling machines are not well adapted for the automatic trip just mentioned except in some instances in the cutting of the relatively large helix angles where the connecting the screw and work piece.

it is an important object of the invention to provide an improvedtransmission and control ar" rangement for cutting of helical 'grooves'of both 30 nism adapted for use with either lead.

Another purpose is to provide such mechanism in which the trip mechanism operates in a simi lar manner both for long and short leads, using same or similar table dogs and the same tri elements at least in such part as is of concern to the operator who is setting up or adjusting the machine. i

Other purposes relate to improved arrangements of transmissions including tool and work spindle trains and feed and quick traverse drives and improved specific relationships thereof for cutting helical grooves or threads oiboth small and. large angle and improved and simplified control mechanism therefor.

Another purpose is generally to simplify and improve the construction and operation of for generating helical grooves or threads particularly on a milling machine and particularly with respect to the transmission and control mechanism.

The invention consists in the construction and combination of parts as herein illustrated, de scribed, and claimed and in such. modifications 55 thereof as may be equivalent thereto.

drive is through the table screw to the gearing long and short lead and including trip mechaa assignor to Trecker Corporation, West Allis,

Serial No. 578.685

Like reference characters indicate the same parts throughout the specification and annexed drawings, in which:

Fig. l is aright side elevation of a typical machine illustrating the invention.

Fig. 2 is a front elevation ,of the same machine.

lug. chine Fig. i is a development of certain mechanism indicated in Fig. 1. p

Fig- 5 is a sectional View on the line 5-5 of Fig. 4.

Fig. 6 is an enlarged front elevation of certain mechanism indicated in Fig. 2.

Fig. '7 is a right side elevation of the same.

8 is a similar View showing a somewhat different set-up.

Fig. 9 is a view of a portion of Fig. 2 with certain parts removed showing a modified form of trip mechanism.

Fig. 19 is a sectional view on the line 10-l0. of Fig. 9.

Fig. 11 is a sectional View on the line 11-11 of Fig. 9. l

1?. is a schematic sectional View. in the nature of a development showing the operative relationship of the various parts of the machine.

As indicated in Fig. 1, the machine comprises a column or support l constituting a foundation for the various parts of the machine. A knee or supportZ is slidably fixed with column 1' and he vertically adjusted along aiace thereof is a plan View ofa portion of the mapartly in sectionalong the line 33 of and clamped therewith when desired. by suitable 1 dividing head or support generally denoted. by

numeral firnounted thereon.- Column l'alsosup ports for rotation a tool spindle or support '1 axia y transverse to normal paths of movement of taale 5 adapted to carry a cutting tool, or the like, not shown, in position for operatingzupon a work piece supported from table 5. Overarms 8 and 9 are adjustably supported from column 1 for use in certain operations of themachine in.

- familiar manner, and a pulley 10 forms a powerv source from which certain of the supports may Gil be operated through appropriate power trains. Movement of knee 2 may be obtained through the actuation of a shaft 11 by means of a crank,

or the like, not shown, applied to a squared portion 12 thereof, the shaft being journaled in knee 2 and actuating, through bevel gears 13 and 14, an elevating screw 15 engaging a suitable thrust bearing 16 fixed with knee 2 and threaded in a nut portion 17 fixed with a pedestal 18 fixed with an extended portion of column 1. Rotation of shaft 11 will accordingly cause rotation of screw 15 and vertical movement of knee 2.

Swivel carriage 3 may be horizontally adjusted relative to knee 2 by means of a screw shaft 19 journaled in knee 2 and prevented from axially moving therein, the screw engaging a nut portion 20 depending from carriage 3 into a suitable recess 21 in knee 2. Screw 19 may be rotated by means of a crank, or the like, not shown, applied to a squaredportion 22 formed on the screw. Dials 23 and 24 are fixed respectively withscrew 22 and shaft 12 in familiar manner for indicating the extent of movement of the members involved.

Table 5 maybe moved by rotation of a table screw 25, Fig. 2, journaled in suitable bearings 26 and 27 fixed with the table and adapted to prevent relative axial movement between the screw and table, the screw engaging a nut portion 28 fixed with saddle 4 whereby rotation of the screw will cause sliding movement of the table. Screw may be rotated by means of a crank, or the like, not shown, applied to a squared portion 29 and a dial 30 may be fixed with the i screw for indicating the extent of the movement in well-known manner. Screw 25 may also be rotated by power, as will be fully described presently.

Turning to Figs. 1 and 12, the train for rotation of spindle 7 is as follows: Pulley 10 is fixed with and drives a shaft 31 journaled in a bracket portion 32 fixed with column 1, the shaft driving through a gear 33 fixed therewith and an idler 34 fixed with a shaft 35, a gear 36 constituting part of a motion interrupting device or clutch generally denoted by numeral 37. Clutch 3'7 drives a shaft 38 journaled in column 1 and driving a shaft 39 through a rate changer generally denoted by numeral 40, shaft 39 driving spindle '7 through gears 41 and 42 meshedtogether and fixed re-- spectively with the shaft and spindle.

Clutch 3'7 comprises outer and inner members 43 and 44 having suitable inter-engaging friction surfaces, member 43 being journaled on shaft 38 and maintained in suitable axial position thereon as by a collar, or the like, 45 and member 44 being slidably keyed with shaft 38. Member 44 may be moved axially into and out of engagement with member 43 by movement of a hand l 'will' accordingly cause disengagement and engagement respectively of member 44 with member 43.

Rate changer 40 comprises a member consisting of gears 55, 56, and 5'7 slidably keyed with shaft 38 and engageable one at a time respectively with gears 58, 59, and fixed with shaft 39. The various gears are of different diameters whereby engagement of different pairs will result in different speeds of operation of shaft 39 and accordingly of spindle 7. Gears 55, 56, and 5'7 may be shifted into engagement with one or another of gears 58, 59, and 60 by means of a hand lever 61 fixed with a shaft 62 extending into the interior of column 1 and carrying a lever 63 which has pivoted theretoa member 64 adapted to engage the sides of gear 56. Movement of lever 61 will accordingly cause sliding movement of gears 55, 56, and 5'7, the parts being retained in desired positions by engagement of a spring plunger or detent member 65 forming a grip portion for lever 61 with suitable sockets or holes such as 66 and 67 formed in column 1.

A feed train for movement of table 5 originates in above mentioned shaft 38, Figs. 1 and 12, the shaft driving, through a rate changer generally denoted by numeral 68, a shaft 69 journalled in a housing portion 70 fixed with column 1, the shaft being coupled, throughan extensible universal joint shaft of well-known construction generally denoted by numeral '71, with a shaft '7 2 journaled in a housing portion 73 fixed with knee 2, shaft '72 carrying a gear 74 forming the terminal ele ment of the feed train.

- Rate changer 68 comprises gears 75, 76, and '77 spaced apart on shaft 38 within housing 70 and engageable one at a time with gears '78, 79, and fixed together and forming a unitary member slidably keyed with shaft 69, the gears being of different diameters whereby engagement of different pairs will result in different rates of rotation of shaft 69. Gears '78, '79, and 80 may be shifted by means of a lever 81 fixed with a shaft 82 extending into housing member '70 and carrying a lever 83 having a member 84 pivoted thereto and engaging the sides of gear '79 whereby movement of lever 81 will cause sliding of gears '78, 79, and 80 and engagement thereof with one or another of gears '75, '76, and 77, the parts being retained in desired positions by means of a spring plunger or detent 85 forming a grip portion for lever 81 and engageable with one or another of sockets or holes such as 86 and 87 formed in housing member '70.

A rapid traverse train for movement of table 5 originates in above mentioned shaft 35 whereby it is operative independently of the condition of engagement'of clutch 3'7. Shaft 35 drives a shaft 88, journaled in housing member 70, through gears 89 and 90 meshed together and fixed with the respective shafts, shaft 88 driving, through an extensible universal joint shaft of well-known construction generally denoted by numeral 91, a shaft 92 journaled in above mentioned housing member '73 fixed with knee 2. Shaft 92 drives, through a motion interrupting device or clutch generally denoted by numeral 93, a gear 94 constituting the terminal of the rapid traverse train.

Clutch 93, as more particularly shown in Fig. 4,

comprises inner and outer members 95 and 96, the

members having suitable interengaging friction surfaces for establishing driving relationship therebetween. Member 95 is slidably keyed with shaft 92 andmember 96 is journaled thereon and fixed with above mentioned gear 94, the members being normally disengaged from each other by means of a compression spring 97. Member 95 may be forced into engagement with member 96 throughdownward movement of a lever 98 fixed with a shaft 99 journaled in a bracket portion 100 fixed with housing 73, shaft 99 carrying a lever 101 having pivoted thereto a shoe 102 engaging an annular groove 163 formed in a projecting portion of member 95 Downward. pressure of lever: 98 will accordingly cause engagement oimember-95 withmember96 against the resistance of: spring: 97, the spring returning the parts to disengaged position upon release of such. downward pressure- The drive continues alternatively from terminal elements 74 and-94 through an overrunning clutch generally denoted by numeral 104 to a shaft 105, Figs. 1 and: 12, journaled in housing 73, the shaft drivingthroughbevel gears 106 and 107 located in. a. housing 198 fixed: with a portion of swivel. carriage 3;. a vertical shaft 109. carrying gear. 110;. Gear 1110, as more particularly shown in Fig;.2,. driveathrough an idler 111 journaled on a; studt 1:12.. fixed: in swivel: carriage 3, av gear 113.

fixed: with a. shaft 114 extending vertically into saddle 4 and driving, through a. reverser generally denotectby'numeral 115,. a clutch or motion interrupter. generally denoted by numeral 116, Fig. 3; the; clutch communicating. motion alternatively to. adrive shaft 117 or to table screw 25 through a gear. 118.: meshing with a gear 119 slidably keyed with table screw 25.

Referring to Figs. 4. and 5, over-running clutch 104 comprises an inner portion 120 journaled on shaft1'95 and driven from gear 74 through a gear/.121 fixed with portion 129. Portion 126 drives an outer portion 122 through a plurality of rolls 123, each roll being disposed in a recess 124: formed in member 120 and adapted through a wedging action caused by the contour of recesses124- to transmit the drive -from member 120 to outer member 122, the roll upon rotation of member 120 in a counterclockwise direction, as

a rigid driving relation is established between members 120 and 122whenever member 120 is rotated in the intended direction. In the event, however; that member 122 is rotated, for example by the above explained rapid traverse train at a rate-inexcess ofthat of member 120, rolls 123 andcage 12'? will be carried around by member 122 in a counterclockwise direction with relation to member 120, the rolls relinquishing their grip upon member 122 and permitting free rotation thereof without interference from or with member 120.

Gear 94 may so drive member 122 through an idler 129 journaled on a stud 130 fixed with bracket portion 131 of housing 73, the idler engaging a gear 132 fixed with member 122.

Reverser 115, Fig. 2', comprises a bevel gear 133 fixed with vertical shaft 114 and driving in opposite directions bevel gears 134 and 135 spaced apart and-journaled in suitable bearings 136 and 137 respectively, Fig. 3, in saddle 4 by means of extended hub portions 133 and 139. The gears havealigned bores through which table screw 25 may freely slide and a clutch member 140 is slidably journaled on screw 25 between gears 134 and 135; there being suitable clutch teeth fixed with member 140' for engagement with clutchteeth formed on gear 134 upon movement of the memberin one direction and other clutch teeth for engagement with clutch teeth formed on gear 135 when the member is moved in the opposite direction; Clutch member 140' drives clutch 116- through a gear 141 and. member 140 may be shifted into engagement. with one or the other of gears 134 and 135 from a hand lever 142 fixed with a shaft 143 journaled in a portion of saddle 4 and actuating. through a gear 144, a rod 145 slidable in saddle 4 and having rack teeth formed therein engaging the gear, a. fork member 146 being fixed with rod 145 and engaging an annular groove 147 formed in clutch member 146. The engagement of clutch member 140 with one r the other of gears 134 and 135 will accordingly drive clutch. member 116 in one or the other direction.

Clutch 116 comprises. a sleeve member 143 journaled on. above mentioned drive shaft'll' and driven from clutch member 146 by means of a gear 149 meshing with. 141, the gears having sufficiently wide faces to allow axial movement of either clutch member without disengagement thereof from the other. Sleeve 148 hassuitabl'e clutch teeth formed thereon for. engagement with clutch teeth formed on a sleeve 150. slidably keyed with shaft 117 and supported in a bearing 151 fixed with saddle sleeve 156 being prevented from axially moving by suitable collars 152, or the like. Sleeve 148 also has clutch teeth for engagement with suitable clutch teeth formed on above mentioned gear 118. Move ment of sleeve 148 in one direction will accord ingly cause driving of shaft while movement thereof in the opposite db. c tion. will cause driving of table screw through. gears 118 and 119, as above outlined.

Sleeve 148 may be so moved from a hand lev 117 from reverser 7' El 155 with a shaft 156 journaled in saddle 4,

and actuating a shifter rod 157 slidable in the saddl the rod having suitable rack teeth engaging a gear 158 fixed with shaft 156 and a shifter fork 159 engaging a suitable annular groove formed in sleeve 143.

Dividing head 6 may be of any suitable or de sired type, in the present instance comprising a housing portion 169, Fig. 3, adapted to be secured to table 5 in any suitable or well-known manner, not shown, and having journaled therein a spin dle or supper" 161'. Spindle 161 may be rotated manually from an index lever or crank 162 fixed with a shaft 163 extending into housing 166 and carrying a worm 164 engaging and driving a worm 1% wheel 165 fixed with spindle 161. Crank 162 may have a grip portion 166 adapted to actuate a spring pressed pin or plunger 167 engaging suitable holes in an index plate 168, the selection of desired numbers of holes determining fractional revolutions of spindle 161 in wellknown manner. Plunger 167 may be locked out of engagement with plate 163 by sui" 1e well-known means, not shown, when desirable, when it is necessary to make se eral compl turns of crank 162 and for convenience in so turning the crank a second grip portion 169, Figs. 1 and 2, is fixed with a portion of crank 162.

Spindle 161 may also be rotated by power for certain purposes, for example, for milling spirals. threads, or the like, through a drive shaft 176 driving, through a reverser generally denoted by numeral 171, a shaft 172 which in turn drives, through bevel gears 173, 174, a shaft 175. Shaft 175 drives above mentioned shaft 163 three, gears 176 and 177 fixed with the respective shafts and connected by means of an idl r 173 journaled on a stud 179 fixed with a portion ofheusing 160;

desired gear 180 being journaled on shaft and gear 181 being fixed with shaft 172, both within a suitable housing 182 and connected by a bevel gear.

or idler 183 fixed with a shaft 184 journaled in housing 182. A clutch member 185 is slidably teeth for engagement when moved in one direction with clutch teeth formed on gear 180 and other clutch teeth for engagement when moved in the opposite direction with clutch teeth formed on gear 181. When clutch member 185 is moved in one direction, for example, to the left in Fig. 3, shaft 170 will drive shaft 172 through clutch member 185 and gear 181, the two shafts rotating in the same direction. When clutch member 185 is moved in the opposite direction, shaft 170 will drive shaft 172 through clutch member 185, gear 180, idler 183, and gear 181, the shafts then turning in opposite directions.

Clutch member 185 may be shifted by means of a hand lever 186, Fig. 2, fixed with a shaft 187 extending into housing 182 carrying a lever 188, Fig. 3, havin a pivoted shoe, or the like, 189

engaging an annular groove 190 formed in clutch -member 185, movement of lever 186 accordingly shifting clutch member 185 into a desired position. Lever 188 has a grip portion 191 comprising a spring pressed plunger adapted to engage sockets or holessuch as 192 and 193, Fig. 2, formed 'sary relative to the rotation of the work piece.

in a portion of housing 182.

Shaft 170 may be driven alternatively from table screw 25 or from above mentioned drive shaft 117 through a rate changer or gear set generally denoted by numeral 194, more particularly shown in Figs. 6, 7, and 8, the rate changer comprising brackets 195 and 196 pivotally supported from an extended portion 197 of housing 182, the brackets being slotted at 198 and 199 respectively and capable of being clamped with portion 197 in various desired positions by means of bolts 200 and 201, the brackets carrying removable gears which may be placed in suitable relations thereon to give the desired driving connections between the several shafts, typical illustrative set-ups being shown in Figs. 7 and 8.

Thus Fig. 7 shows a set-up for cutting a thread or spiral, or the like, having a relatively small lead, shaft 170 in this instance preferably being driven from above mentioned drive shaft 117,

table screw 25 then being driven from shaft 170 through suitable gears, the result being to avoid a step-up in speed which would otherwise be necessary between the screw and shaft 170. A gear 202 is removably fixed with shaft 117 and drives a gear 283 removably fixed with shaft 170 through idlers i and 205 journaled respectively on studs 206 and 207 adjustably fixed in a T-slot 208 in bracket 198, a second T- lot 209 being provided in the bracket for use when necessary in other set-ups. fixed with table screw 25, through an idler 211 journaled on a stud 212 adjustably fixed in a T-siot 213 in bracket 195. With this arrangement of gear set 194, above mentioned, clutch 116, Fig. 3, would be set to drive shaft 117, clutch member 148 engagingv sleeve member 150, and table screw accordingly being free to be driven independently of clutch 116 as, for example, by .means of gear set 194. V

The particular advantage in driving table screw 25 indirectly in this manner may be outlined as follows: In the event/that a small lead is desired in a spiral or thread being cut, rela- .tively slow rotation of the table screw is neces- Gear 203 drives a gear 210, removably- The rotation of shaft 170 is, of course, propor-' tional to the rotation of the work piece and accordingly relatively rapid. With the conventional arrangement of gears between screw 25 and shaft 170 it would accordingly be necessary to use a relatively low feed on the table screw and then by means of suitable gearing step up the rotation of shaft 170 to the necessary high rate, such arrangement giving relatively poor efficiency and introducing large stresses in the gearing, particularly if it is desired to use the rapid traverse for idle movements of table 2, the speed of shaft 170 then becoming excessive. With the present arrangement a reasonable ratio between shaft 117 and shaft 170 may be adopted and a high enough feed selected to give the necessary rate of rotation in shaft 170, this rate then being reduced through gears 203, 211, and 210 to the proper speed in table screw 25. The efficiency under these conditions would normally be very good and the use of the rapid traverse would not step up the speed of shaft 170 to any unreasonable figure, the resulting stresses in the gearing being entirely within reason. The set-up shown in Fig. 8 is illustrative of the operation when cutting a spiral having a relatively long lead, in this instance a gear 214 fixed with table screw 25 driving gear 203 fixed with shaft 170 through. idlers 216 and 217 journaled each respectively on studs 218 and 219 adjustably fixed respectively in T-slots 213 and 220 in bracket 195. In this situation clutch 116, Fig. 3, is engaged to drive table screw 25, clutchmember 1 18 being engaged with gear member 118 and accordingly disengaged from sleeve member 150. Shaft 11'? may be allowed to run idle, driven from gear 283 through above mentioned idlers 28 i and 285 driving gear 202 or bracket 195 may be rotated slightly about portion 197, as shown, to disengage idler 285 from gear 282, as indicated, or, if desirable, of course, idlers 20 1 and 205 may be removed entirely from bracket 196. With this set-up there will obviously be no loss of efficiency through excessive speed in shaft 170 even when the rapid traverse is used for table movement and the stresses in the gearing may always be kept within the bounds of good practice.

Automatic stop of table movement may be obtained at any desired point in the movement of table 5 by any suitable or well-known means, in

the present instance comprising dogs 221 and, 222, Figs. 2 and 12, adjustably fixed with table 5 by means of bolts, or the like, 223 and 2241 respectively, engaging a suitable T-slot 225 formed in the table, the dogs actuating respectively plungers 226 and 227 vertically slidable in saddle i and having suitable rack teeth engaging opposite sides of a gear 228 fixed with above men tioned shaft 143. The arrangement of the parts is suchthat table 5, when screw 25 is driven through reverser 115 and clutch 116, will feed or traverse in the direction in which lever 142 is moved. In order to make available the automatic stop, it is essential that this relation be preserved and it is accordingly important when table screw 25 is driven indirectly through drive shaft 117 that the requisite number of idlers, including any gear on shaft 170, be provided to drive screw 25 in a direction opposite to that of shaft 117,

as is the case when the screw is driven through clutch 116 and gears 118 and 119. Reverser 171 may then be utilized to obtain the desired direction of rotation of dividing head spindle 161, regardless of the direction of rotation of shaft 170,

and incidentally it is possible to form either a l right-hand or a left-hand spiral with the same arrangement of 'gearrset 194 and with either direction of table movement by proper setting of reverser 171. r

In some instances it may be found preferable to utilize a slightly different type of .trip mechanism for stopping table 5 whereby it will be unnecessary to maintain the relative directions of rotation between drive shaft 117 and table screw 25. Such a mechanism, for example, comprises, as shown in Figs. 9, l0, and 11, plungers 229 and 230 vertically slidable in a portion of saddle e and situated in a plane transverse to the path of movement of table 5. Plunger 229 has rack teeth engaging a gear 231 forming part of a member 232 fixed with a shaft 233 journaled in saddle i, the shaft having a hand lever 234 fixed therewith for manual operation. Plunger 230 has rack teeth engaging a gear 235 fixed with a shaft 236 journaled in saddle 4. Gear 235 meshes with and drives a gear 23? fixed with above mentioned shaft 143 and a gear 233 forming part of member 232 also meshes with gear 23"! whereby movement of one plunger downwardly will cause rotation of shaft 143 in one direction and raising of the other plunger. Plunger 229 may be contacted at a predetermined point in the movement of table 5 by a dog 239 fixed by means of a belt 240 with above mentioned T-slot 225 formed in table 5, and plunger 230 may be similarly contacted by means of a dog an, fixed with table 5 by means of a bolt 242 acting in T-slot 22-5, the dogs extending diiferent distances from table 5, as more particularly shown in Fig. 12,,whereby either dog may contact one plunger but not the other. It thus becomespossible to cause automatic stop of table 5 regardless of the direction or" movement of the table relative to the movement of lever 234, it being merely necessary to position the appropriate dog for contacting the particular plunger which happens to be raised. With this arrangement of trip plungers it is accordingly possible to set up the gears in rate changer 15 4 without regard for the resulting direction of rotation of table screw 25 with the assurance that an automatic stop of the table may be obtined by merely suitably positioning dogs 239 and 241. As in the previous case, reverser 166 be utilized to obtain the desired direction of spindle 16?. regardless of the direction of rotation of shaft 17s, the reverse also permitt" hand spirals in either direction of table movement without regard for the particular arrange- :..1ent of gears in rate changer 194. For use in co unction with dividing head 6 a tailstock oi wknown type generally denoted by numeral Figs. 1 and 12, may be fixed with table 5 by suitable or well-known means.

above being a full. and complete descripti of an illustrative embodiment of the inventron, what is claimed is:

1. In a milling machine, the combination of a rotatable tool spindle, a rotatable work spindle, a support movable for relative bodily reciprocatory movement of said spindles, a screw element and a nut element relatively rotatable for establishing said reciprocatorymovement, a motion transmitting connection including rate change gearing and connecting one of said screw and nut elements with said work spindle for establishing predetermined relative rates of rotation thereof, alternative power trains connectible with the last mentioned element, one of said trains including said gearing and the other excluding ance with said reciprocatory movement during g the formation of either right of left-' rotatable tool spindle, a rotatable work spindle, a

support movable for relative bodily reciprocatory movement of saidspindles, a train including rate change gearing and interconnecting said support and work spindle for determining the relative rate of said reciprocatory and rotary movements, a power source, mechanism for connecting said power source alternatively to drive said train between said work spindle and said gearing or between said gearing and said support, said mechanism including motion interrupting means operable to i terrupt the driving one of said alternative driving connections to said train, and a trip device dog operable in accordance with said reciprocatory movement during either of said alternative driving connections for the operation of said motion interrupting means.

3. In a milling machine, the combination of a rotatable tool spindle, a rotatable work spindle, a support movable for relative bodily reciprocatory movement of said spindles, a screw element and a nut element relatively rotatable for estab lishing said reciprocatory movement, a motion .J'

transmitting connection including rate change gearing and connecting one or" said screw and nut elements with said work spindle for stablishing predetermined relative rates of rotation thereof, alternative power trains for driving the last mentioned element through said gearing or exclusive thereof, a shiftable motion interruptiondevice common to both said power trains and operable to interrupt the driving one of said alternative driving connections thereof, and a trip device dog operable in accordance with said reciprocatory movement during either of said alternative train connections and connected for shifting said motion interrupting device.

4. In a milling machine, the combination of a rotatable tool spindle, a rotatable work spindle, a support movable for relative bodily reciproctory movement of said spindles, a screw element and a nut element relatively rotatable for establishing said reciprocatory movement, a motion transmitting connection including rate change gearing and connecting one of said screw and nut elements with said work spindle for establishing predetermined relative rates of rotation thereof, a transmission for said tool spindle ineluding a motion interrupter, a feed transmission driven from said tool spindle transmission through said motion interrupter and including a rate changer, alternative power trains for driving the last mentioned screw and nut element from said feed transmission through said gearing or e:-:clusive thereof, feed interrupting means for disconnecting said feed transmission from said alternative power trains, and a trip device dog operable in accordance with said reciprocatory movement during either of said alternative train connections for the operation of said feed interrupting means.

5. In a milling machine, the combination or" a rotatable tool spindle, a rotatable work spindle, a support movable for relative bodily reciprocatory movement of said spindles, a screw element and a nut element relatively rotatable for establishing said reciprocatory movement, a motion transmitting connection including rate change gearing and connecting one of said screw and nut I ioi) power trains being alternatively operable from said feed train or from said quick traverse train, means shiftable for disconnecting the connected one of said power trains and a power trip operable in accordance with said reciprocatory movement during either connection of said power trains and connected for operation of said shiftable means.

FRED A. PARSONS. 

